Electron Microscopy of Effect of Polymyxin on
            <i>Escherichia coli</i>
            Lipopolysaccharide

Lopes, João Brisson; Inniss, W. E.

doi:10.1128/jb.100.2.1128-1130.1969

Cited by 83 publications

(28 citation statements)

References 9 publications

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“…It has previously been shown that surface active agents such as sodium lauryl sulfate and sodium deoxycholate disaggregate the LPS (26,35). Polymyxin antibiotics also show similar effects on bacterial LPS as demonstrated by disappearance of endotoxic activity (36) and the disruption of the membrane-like structure typical of LPS (23). Polymyxin B also liberates the periplasmic penicillinase of GI Ila I without any concomitant release of ,B-galactosidase (42).…”

Section: Resultsmentioning

confidence: 88%

Ampicillin-Resistant Mutants ofEscherichia coliK-12 with Lipopolysaccharide Alterations Affecting Mating Ability and Susceptibility to Sex-Specific Bacteriophages

1971

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Mutations from moderate (class I) to high (class III) ampicillin resistance in a male and a female strain of Escherichia coli K-12 have been found to be accompanied by surface alterations, first demonstrated as hindrance in the formation of mating pairs. These changes have now been studied with the ribonucleic acid phage MS2, and especially with the "female-specific" phage OW. Several class III mutations in male and female strains were found to make the cells susceptible to phage 4W and to reduce their abilities to form mating pairs. Spontaneous phage OW-resistant mutants isolated from class III strains were found also to have acquired changes in ampicillin resistance and ability to form mating pairs. One mutant had reverted to parental class I type in all three properties. Lipopolysaccharides (LPS) prepared from OW-sensitive class III strains inactivated the phage in vitro, whereas LPS from phage-resistant strains had no effect. Carbohydrate analyses of LPS preparations showed that two class III mutants, compared to their parental strains, had lost significant parts of the rhamnose, galactose, and glucose from the LPS. One of the phage OW-resistant mutants showed a partial restoration of its carbohydrate composition. Other OW-resistant mutants showed, instead, further losses of carbohydrates in their LPS. It is suggested that genes exist which simultaneously mediate a female-specific mating site, ampicillin resistance, and the receptors for phage OW.III mutations in either the Hfr or the female cells (3). We have now isolated several new mutants and studied this surface effect by using the sex-specific phages MS2 and OW. Efficiency of plating (EOP), killing of host cells, and adsorp-on July 31, 2020 by guest

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Section: Resultsmentioning

confidence: 88%

Ampicillin-Resistant Mutants ofEscherichia coliK-12 with Lipopolysaccharide Alterations Affecting Mating Ability and Susceptibility to Sex-Specific Bacteriophages

1971

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“…The electron microscopic examination of uranyl formate stained LPS from S. typhimurium strain 7 (12) and E. coli 018 (23) showed a ribbon-like structure (fila- mentous form) with branching, whereas, LPS from S. typhimurium stained with ammonium molybdate showed a spherical structure (19). Ribi et al (18) and Lopes and Innes (13) reported that LPS isolated from S. enteritidis S-795 and E. colt 018, respectively, appeared as branching ribbons when stained with phosphotungstate and tungstate.…”

Section: Discussionmentioning

confidence: 99%

Chemical and Ultrastructural Comparison of Endotoxins Extracted from Salmonella minnesota Wild Type and R Mutants

Amano

Fukushi

1984

Microbiology and Immunology

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Endotoxic lipopolysaccharide and glycolipids (RGl) extracted from Salmonella minnesota wild type and R mutant cells (chemotypes Ra, Rb, Re, Rd1, and Rd2), respectively, with hot phenol‐water (PW) and phenol‐chloroform‐petroleum ether (PCP) were analyzed chemically and electron microscopically. All RGl extracted with PW (RGl‐PW) contained excess amounts of phosphate, O‐ester linked fatty acids and neutral sugars, while all RGl extracted with PCP (RGl‐PCP) contained excess amounts of free amino groups and fatty acids, in addition to the RGl constituents. Polyamine (cadaverine), phosphoethanolamine, and an unidentified amino compound were contained in RGl‐PCP as free amino groups. When stained with uranyl formate, the ultrastructure of RGl‐PW showed a spherical form (onion‐like form), whereas the micrographs of RGl‐PCP showed a filamentous structure, regardless of strain differences. On the other hand, the micrographs of RGl‐PW represented spherical and doughnut‐shaped forms, and the micrographs of RGl‐PCP showed filamentous or stick forms, when stained with uranyl acetate. Thus, it is suggested that the ultrastructures of RGl were dominated by the solvent systems used for extraction, and not by the strains used here.

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“…The precise nature of the interaction of PB with LPS and its haptenated derivative is unknown, although work on model membrane systems and the selective toxicity of PB for gram-negative bacteria suggest that the presence of phosphatidylethanolamine in the LPS of bacterial cell walls is important (11)(12)(13)(14)(15)(16)(17)Footnote 1) . An interaction might also be expected between the highly charged PB, which contains five y-amino groups, and the phosphate groups of LPS .…”

Section: Discussion and Summarymentioning

confidence: 99%

Dissociation between mitogenicity and immunogenicity of TNP- lipopolysaccharide, a T-independent antigen

Jacobs¹,

Morrison²

1975

The Journal of Experimental Medicine

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Two models have been proposed to explain triggering of B cells by so-called T-independent antigen. Feldmann and Basten (1) proposed that the interaction of multiple repeating determinants on polymeric antigens with specific Ig receptors on the B-cell surface is sufficient to provide the signals for division of these cells and differentiation to antibody-forming cells. In contrast, coutinho et al. (2, and see review, 3) have claimed that there is only one signal, a mitogenic signal, receptors acting merely as passive focusing devices to localize the antigen on specific cells where it delivers a mitogenic signal resulting in differentiation to an antibody-producing cell. This model rests primarily on the demonstration that at high concentration all T-independent antigens they have tested are mitogenic for B cells (4-6). Compatible with this hypothesis are the observations that hydrolysis of lipopolysaccharide (LPS) to remove the ester- linked fatty acids of the mitogenic lipid A component abrogates its mitogenic (7,8) activity as well as its ability, when substituted with the TNP hapten, to induce a T-independent anti- TNP response (9). However, alkali treatment of LPS, although not changing its antigenic component (8), may also modify the molecule physically or chemically which could account for loss of immunogenic properties (10). We therefore investigated other reagents which interact with LPS in a more chemically defined manner in an effort to clarify the relationship between the mitogenic and immunogenic properties of this molecule. Polymyxin B (PB) is one of a family of cyclic peptide antibiotics which are bactericidal for most gram-negative bacteria. It prevents the lethal endotoxic activity of LPS (11, 12) and changes the physical structure of LPS (13). We report here that low doses of PB added to cultures of mouse spleen cells inhibit the mitogenic activity of TNP-LPS, a T- independent antigen, and native LPS, but do not suppress the immune response to TNP-LPS. PB interacts with TNP-LPS and LPS causing a physical change in the molecule. In addition, polymyxin-treated LPS is no longer mitogenic. These results suggest a dissociation between the mitogenic and immunogenic properties of TNP-LPS.

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Electron Microscopy of Effect of Polymyxin on Escherichia coli Lipopolysaccharide

Abstract: Polymxyin treatment of isolated lipopolysaccharide from Escherichia coli resulted in the breakdown of its structure.

Cited by 83 publications

References 9 publications

Ampicillin-Resistant Mutants ofEscherichia coliK-12 with Lipopolysaccharide Alterations Affecting Mating Ability and Susceptibility to Sex-Specific Bacteriophages

Ampicillin-Resistant Mutants ofEscherichia coliK-12 with Lipopolysaccharide Alterations Affecting Mating Ability and Susceptibility to Sex-Specific Bacteriophages

Chemical and Ultrastructural Comparison of Endotoxins Extracted from Salmonella minnesota Wild Type and R Mutants

Dissociation between mitogenicity and immunogenicity of TNP- lipopolysaccharide, a T-independent antigen

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